A systematic review on guanitoxin: General characteristics and ecological risks.

Guanitoxin (GNT) is a potent cyanotoxin, with a relatively low number of publications (n = 51) compared to other cyanotoxins. Among the published studies, 35 % were on the effect of the toxin in animals, mainly in rodents and in vitro testing, followed by studies that identified species of cyanobacteria that produce GNT in aquatic systems and consequently accidental poisoning in wild and domestic animals (27 %). Studies that developed or tested methods for identifying the molecule, based on colorimetric and analytical techniques, represented 14 %, while 8 % were on GNT biosynthesis. Review articles and chemical isolation (6 %) and on the stability of the molecule (4 %) were the topics with the lowest number of publications. The results show the occurrence of GNT was identified mainly in eutrophic environments with a higher incidence in the American continent. Chemical characteristics of the molecule, such as short half-life in the environment, instability in solutions with alkaline pH values, temperature >23 °C, added to the lack of an analytical standard, are factors that make it difficult to identify and quantify it. However, GNT monitoring can be performed using LC-MS-MRM methods or genes specific to the newly discovered molecule.